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Geneva, 28 May 2010
PBB-TE Infrastructure Protection Switching Operation
Bob Sultan,Huawei Technologies
Joint ITU-T/IEEE Workshop on The Future of Ethernet Transport
(Geneva, 28 May 2010)
Geneva, 28 May 2010 2
Topics
Review PBB-TE ForwardingThe Infrastructure Segment and IPGMonitoring the SegmentProvisioning an IPGInfrastructure Protection Switching
Geneva, 28 May 2010 3
Ethernet Switched Path (ESP) forwarding is based on provisioned 2-tuple <Destination MAC, VLAN Identifier> and associated outbound local port;
PBB-TE Forwarding (ESP)
DCBA E
Port Out<DA, VID><E, 7> P2
P1
P3P2
P1
P2
P3 P1
P3
P2
Port Out<DA, VID><E, 7> P3
Port Out<DA, VID><E, 7> P1
Filtering Database (FDB) B FDB D
FDB C
ESP X
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A pair of counterdirectional congruent PtP ESPs form a PtP Traffic Engineered Service Instance (TESI);IPS also applies to linear portions of PtMP TESIs;
PBB-TE Forwarding (TESI)
DCBA E
Port Out<DA, VID><E, 7> P2
P1
P3P2
P1
P2
P3 P1
P3
P2
Port Out<DA, VID><E, 7> P3
Port Out<DA, VID><E, 7> P1
Filtering Database (FDB) B FDB D
FDB C
<A, 8> P2
<A, 8> P1
<A, 8> P1
ESP x
ESP yTESI
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A segment is specified by a sequence of ports:
Green: B.P2 – C.P1 – C.P3 – D.P2Red: F.P2 – G.P1 – G.P2 – H.P2
Bridge terminating a segment contains exactly one port associated with that segment;
Segment
DCBA EP1
P3P2
P1
P2
P3 P1P3
P2ESP x
HGFP1
P2
P1
P2
P2
P1
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The state of an Infrastructure Segment is monitored by a Maintenance Association (MA) specific to that Segment;Distinct type of MA; not the same as the PBB-TE MA associated with a TESI;
Terminates at PBP vs. CBP;Down MEPs vs. Up MEPs;
Segment Monitoring
DCBA E
Green MEP Green MEPGreen Segment MA
CCM
CCM
CCM
CCM
CCM
CCM
J
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Non-overlapping segments having the same pair of segment endpoint bridges (SEB) form an IPG;A Bridge maintains a table for each IPG terminating in that Bridge (just one shown in this figure);The table contains a list of 2-tuples representing traffic provisioned to follow one of the Infrastructure Segments which is known as the Working Segment;
Infrastructure Protection Group (IPG)
DCBA E
HGF
SEB SEBI
IPGIPGWorking Segment
<J, 11><E, 7>
<I, 9>
<A, 6>
J
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The Protection Segment provides an alternate path for traffic associated with the listed 2-tuples for the IPG;The IPG maintains the local port numbers associated with the Working and Protection Segments respectively;
Protection Segment
DCBA E
HGF
SEB SEBI
IPGWorking Segment
Protection Segment
P3
P2 P2
P3
WS: P2PS: P3
IPGWS: P2PS: P3<I, 9><A, 6>
<J, 11>
<E, 7>
Protection Segment Provisioning
J
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Same list of 2-tuples at F, G, H; but provisioned as if traffic was forwarded on Protection Segment;
DCBA E
HGF
I
P3
P2 P2
P3
Port Out<DA, VID>
<E, 7> P2
FDB B
<A, 8> P1
<J, 11> P2<I, 9> P4
P1
P4
Port Out<DA, VID>
<E, 7> P2
FDB F
<A, 8> P1
<J, 11> P2<I, 9> P1
P1P2
<I, 9>
IPGWS: P2PS: P3
<A, 6>
IPG
<J, 11>
<E, 7>
WS: P2PS: P3
Infrastructure Protection Switching
J
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Protection switch triggered by detection of state change in IPG Segment or manually;Requires FDB update only at endpoint bridges;Update only entries with 2-tuple in IPG list;
DCBA E
HGF
I
IPG
<J, 11>
<E, 7>
<I, 9>
P3
P2 P2
P3
WS: P2PS: P3
IPGWS: P2PS: P3
Port Out<DA, VID>
<E, 7> P2
FDB B
<A, 8> P1
<J, 11> P2<I, 9> P4
P1
P4
P1P2
X
Port Out<DA, VID>
<E, 7> P1
FDB D
<A, 8> P2
<J, 11> P4<I, 9> P2
P3
P3
P1
P4
P3
P3
<A, 6>
Further Points
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The IPS State Machine is identical to the TESI Protection State Machine
Except for the lowest-level functions that update the FDB outbound port values instead of changing the mapping from backbone service instance to BVID;The TESI Protection State Machine is similar, but not identical, to the G.8031 State Machine;
IPS specifies optional M:1 protection, deployed by using an alternate Protection Segment when a Protection of higher priority is not available;IPS supports the nesting of IPGs but this requires appropriate provisioning of hold-off timer values;
Further, the MA associated with the outer IPG must be provisioned to be protection switched by the inner IPG when a failure of the inner IPG occurs;
Thank You
Geneva, 28 May 2010 12
